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Verification
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VHDL / Sequential Statements

case statement

Learn case statement in VHDL through a focused explanation, a dedicated construct-specific example, an engineering boundary, and a mastery check.

10 min read • Intermediate

case statement is an atomic VHDL topic inside Sequential Statements. This lesson focuses on how the case statement construct is written, what it changes, and when it is the right tool.

Trace the example line by line. Identify the exact syntax for case statement, the input state before it runs, and the resulting value, control flow, database state, hardware behavior, or runtime effect afterward. Neighboring lessons use different constructs rather than renamed copies of this one.

Topic-specific example

vhdl-05-02-case-statement.vhd
vhdl Try It Live 
process(all) begin case sel is when "00"=>y<=a; when "01"=>y<=b; when others=>y<='0'; end case; end process;
Edge case / engineering note

For case statement, test the boundary that belongs to this exact feature rather than a generic failure case. Check invalid or empty input, NULL/unknown state, numeric limits, transaction or exception behavior, synthesis/runtime constraints, ownership/permission rules, or backtracking/control-flow effects where they apply.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

case statement Mastery Check →
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if elsif
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for loop